This invention relates to data processing systems. The invention is particularly, although not exclusively, concerned with data processing systems of the kind usually referred to as personal computers. Such computers are normally used by non-computer-oriented persons, or inexperienced users. It is therefore desirable that they should provide functions which are natural in their operation and easy to use with little or no training and minimal reference to documentation.
Such a system may be designed to allow a plurality of different application programs to be executed concurrently. For example, it is possible to run a word processing program while at the same time running a program which is accessing a remote database. Normally, a personal computer is provided with just a single screen, to keep the cost to a minimum. In order to view the states of the different applications programs, it has been proposed to use a "windowing" technique, in which the screen is divided into a number of separate areas, each of which is allocated to a different program. Thus the user can, for example, refer to data retrieved from the database while using the word processing program. However, the windowing technique is inconvenient, since it introduces extra complexity in the system and restricts the screen area available to each program.
One object of the present invention is to provide a way of dealing with this problem which is more convenient than the windowing technique and which is suitable for use by the inexperienced user.